Electrical resistor testing fixture and testing chamber

ABSTRACT

A modular test tray is comprised of individual modules solidly detachably secured together and shorting straps for rapid and easy electrical connection between modules. Each module is comprised of two tuning fork shaped connector pins embedded in the module and capable of detachable mechanical and electrical engagement with the shorting straps. Two posts capable of receiving electrical components to be tested are also embedded in the module and electrically connected to the connector pins. The posts protrude from the top of the module while the connector pins are recessed in grooves on the bottom of the module. Shorting straps consisting of intermittent strips of electrical conducting material, the strips being of sufficient length to electrically connect only two connector pins of adjoining modules and spaced apart so as to electrically connect consecutive pairs of connector pins, allows a series electrical connection of the components to be tested. Shorting straps consisting of continuous electrical conducting material allow a parallel electrical connection of the components to be tested. The individual modules are selectively detachably mounted together to provide easy replacement of worn out modules and to allow variance of the test tray size to accommodate multiple lots sizes and value splits of components.

A testing chamber is generally comprised of a support structure, drawersfor holding the modular test trays, timer, power supplies, and airblower. The support structure supports a plurality of drawers inhorizontal position with the drawers supporting a plurality of testtrays in a horizontal, parallel alignment. When a particular test allowsair flow, air is blown into the plenum of the support structure, andpasses through outlets of the support structure and into mating airinlets of the plena of the drawers. Flapper valves provide control ofthe air flow at the support structure outlets. The air then passesthrough a diffusing medium covering the slots of the drawers and upthrough air passages in the test tray such that there is no directimpingement of air on the components mounted on the modules. Thediffusing medium maintains the air flow through the slots of the drawersat a uniform velocity whether test trays are present or not.

It is a principal object of the invention to provide a modular test traythat allows easy and quick variance of the size of the test tray toaccommodate multiple lot sizes and value splits of the components to betested, and to eliminate wasted space in the test chamber. A furtherobject of the invention is to provide easy repair in that individualmodules can be easily removed and replaced yet still maintaining thebalance of the tray that was operational. A still further object of theinvention is to provide a modular test tray that allows for apressurized chamber so air can flow up between the units taking awayheat and yet not allowing direct impingement of air on the components tobe tested. A still further object of the invention is to provide amodular test tray that is solid in construction and can be used fortests such as shock and vibration and allow positive transfer of energy.A still further object of the invention is to provide a modular testtray that can be wired quickly and easily in either a series or parallelwiring to the same tray. A still further object of the invention is toprovide a modular test tray having a minimum of electrical connection sothat the resistance contact to the part is kept at a minimum. A stillfurther object of the invention is to provide a modular test tray thatfacilitates scanner reading in that all units on a tray can be read in amatter of seconds without unmounting from the tray, including Kelvin (4terminal) readings. A still further object of the invention is toprovide a modular test tray to be used in a wide variety of tests,including moisture, load life, shock and vibration. A still furtherobject of the invention is to provide a testing chamber capable ofproviding non-impinging uniform velocity air flow to the components tobe tested.

BRIEF SUMMARY OF THE INVENTION

A modular test tray and testing chamber are disclosed. The modular testtray is comprised of individual modules detachably mounted for varianceof the tray size and easy replacement of worn out modules. Individualmodules are comprised of embedded tuning fork shaped connector pinselectrically connected to embedded posts capable of receiving thecomponents to be tested. The connector pins detachably receive shortingstraps and allow reading of all units on a tray in a matter of secondswithout unmounting the components from the tray. Shorting straps allowparallel and series electrical connection of the components to betested. Rigid attachment of the modules allow the tray to be used forshock and vibration tests and allows positive transfer of energy, inaddition to electrical tests.

The testing chamber is disclosed wherein the chamber is comprised ofdrawers for supporting a plurality of test trays in horizontal parallelalignment. The testing chamber includes a timer, power supplies, airblower, and support structure capable of supporting the drawers andcontrolling and guiding the air flow from the blower to the test trays.A flapper valve controls the air flow from the support structure to theplena of the drawers. A diffusing medium covering the slots of thedrawers directly beneath the test trays provides uniform velocity of airflow and non-impingement of air on the components.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially exploded perspective view of the modular testtray.

FIG. 2 is an enlarged top view of an individual test tray module.

FIG. 3 is an enlarged sectional view seen on line 3--3 of FIG. 2.

FIG. 4 is an enlarged perspective view of a connector pin and post.

FIG. 5 is a schematic view of the modular test tray in a parallel mode.

FIG. 6 is a schematic view of the modular test tray in a series mode.

FIG. 7 is a perspective view of the testing chamber.

FIG. 8 is a partial top view of the testing chamber drawer and modulartest trays.

FIG. 9 is a sectional view seen on line 9--9 of FIG. 2 illustrating airflow.

FIG. 10 is a partial sectional view seen on line 10--10 of FIG. 7illustrating air flow.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The modular test tray 10 is generally comprised of a plurality ofindividual modules 12, bolt 14, nuts 16 and shorting straps 18.

Module 12 is comprised of "tuning fork" connector pins 20, componentposts 22 and insulating body 24. Connector pin 20 and post 22 areelectrically connected and vertically embedded in body 24 with the upperportion 26 of component post 22 protruding from the surface 28 of body24.

Post 22 has a tuning fork shaped upper portion 26 and a cylindricalshaped bottom portion 30 for slidably engaging the stem 32 of connectorpin 20. Posts 22 are embedded in body 24 such that the grooves 34 ofupper portion 26 are laterally aligned to receive and electricallyconnect to the components to be tested as shown in FIGS. 1 and 3.Connector pins 20 are embedded in body 24 such that grooves 36 ofconnector pins 20 of adjoining modules 12 are longitudinally aligned toreceive and electrically connect to shorting straps 18.

Module 12 has a longitudinal circular aperture 38 for receiving bolt 14and longitudinal grooves 40 for receiving shorting straps 18. The frontedge 42 of modules 12 is provided with tongues 44 to engage the grooves46 provided on the back edge 48 of adjoining modules 12 in a tongue andgroove fashion, such that circular apertures 38 are in longitudinalalignment to receive bolt 14 and grooves 40 are in longitudinalalignment to receive shorting straps 18. A plurality of modules 12 arealigned in tongue and groove fashion as shown in FIG. 1 with the tongues44 engaging the grooves 46 of the adjoining modules 12. The plurality ofmodules 12 are securely joined together by apertures 38 receiving bolt14 and nuts 16 threadably engaging each end of bolt 14 to form a rigidsolid test tray. Grooves 40 are longitudinally aligned to receiveshorting straps 18 which are in turn received by connector pin groove 36such that shorting straps 18 are securely held by and electricallyconnected to connector pin 20 as shown in FIG. 3. Front edge 42 and backedge 48 are provided with recesses 58 such that air flow openings 60 areformed when the modules 12 are joined together as a tray as shown inFIG. 1.

The shorting straps 18, shown in FIG. 1, are constructed of stiffelectrically insulating material with intermittent strips 50 ofelectrical conducting material. Strips 50 are of sufficient length toelectrically connect only two connector pins 20 of adjoining modules 12and are spaced so as to electrically connect consecutive pairs ofconnector pins 20. Lead wires 52 are electrically connected to each endof only one strap 18 as shown in FIG. 1. If an uneven number ofresistors were being tested, the leads 52 would be connected to one endof strap 18 and to the opposite end of the other strap 18. Shortingstraps 18 are inserted in tray 10 such that each strap 18 connectsconsecutive non-opposite pairs of connector pins 20 to produce a serieselectrical connection of the components to be tested as shown in theschematic diagram of FIG. 6.

An alternate form of shorting strap is constructed such that strips 50are adjoining rather than spaced apart so as to form one continuouselectrical conducting strip whereby insertion of the strap into testtray 10 electrically connects all the connector pins 20 on one side oftray 10. Lead wires are electrically connected to one end of eachshorting strap. When both shorting straps are inserted into tray 10, aparallel electrical connection of the components to be tested isproduced as shown in the schematic diagram of FIG. 5.

In operation, the components to be tested are inserted in grooves 34 ofposts 22 of modules 12 as shown in FIG. 1. If a series test is to bemade, shorting straps 18 are inserted in grooves 40 of modules 12 and inturn into grooves 36 of connector pins 20. The components to be testedare now electrically connected in a series configuration as shown inFIG. 6. Points 56 in FIG. 6 correspond electrically to lead wires 52.The test equipment is then connected to lead wires 52.

Similarly, if a parallel test is to be made, the alternate form ofshorting straps are likewise inserted in test tray 10 and the componentsto be tested are thereby electrically connected in a parallelconfiguration as shown in FIG. 5. Points 56A in FIG. 5 correspondelectrically to the lead wires attached to the alternate form ofshorting straps. The test equipment is then connected to the lead wires.

Since the tray is solidly connected, it can also be used for shock andvibration tests. Easy access to the connector pins 20 also facilitatesscanner reading in that all units on a tray can be read in a matter ofseconds without unmounting from the tray.

Test tray 10 is easily and quickly dismantled by disengaging nuts 16 andbolt 14 allowing variance of the tray sizes to accommodate multiple lotsizes and value splits. Worn out portions of the tray may be discardedwhile still maintaining the balance of the tray that is operational.

Testing chamber 62 is generally comprised of support structure 64,drawers 66, timer (not shown) power supplies 68 and air blower 70.

Support structure 64 as shown in FIG. 7 is comprised of drawer slides 72for receiving and supporting a plurality of drawers 66, plenum 74, airflow openings 76 and flapper valve 78. Plenum 74 is enclosed except forair flow openings 76.

Drawer 66 supports test trays 12 in slots 84 in horizontal parallelalignment as shown in FIGS. 7 and 8. Drawer 66 is enclosed except forair flow inlet 80 at one end of drawer 66 (as shown in FIG. 10), and airflow exits 82 on the top surface of drawer 66 directly beneath test tray10 as shown in FIGS. 8 and 9. Diffusing medium 90 is a sheet having aplurality of apertures and covers air flow exits 82.

Test trays 10 are placed in slots 84 of drawer 66 directly above airflow exits 82. Drawer 66 is placed on drawer slides 72 and pushed intosupport structure 64 until meeting plenum 74. Air flow inlet 80 is indirect alignment with air flow openings 76 as shown in FIG. 10.

Blower 70 discharges air into plenum 74. The air is forced out of airflow openings 76, through air flow inlet 80 into the plenum 88 of drawer66 as shown in FIG. 10. Flapper valve 78 provides control of the amountof air that enters each drawer. The air then escapes through diffusingmedium 90 and air flow exits 82 of drawer 66 and up through air flowopenings 60 of test trays 10 such that there is no direct airimpingement on the components mounted on the modules 12. The diffusingmedium maintains the air flow through air flow exits 82 at a uniformvelocity all along exit 82 whether test trays are present or not.

Thus, it can be seen that the modular test tray and testing chamberdescribed accomplishes at least all of its stated objectives.

What is claimed is:
 1. An electrical component testing chambercomprising, at least one modular test tray, at least one drawer having atop portion having a plurality ofgrooves for receivably supporting saidmodular test trays in horizontal parallel alignment, a first plenumwithin said drawer having slots beneath said grooves for allowing airflow and having an air inlet at one end of said drawer to receive airflow, a diffusing means covering said slots for maintaining uniform airvelocity through said slots, a support structure slidably supportingsaid drawers in vertical alignment horizontally parallel to each other,a second plenum within said support structure having air outlets meetingsaid drawer air inlets when the drawer is slidably engaged in saidsupport structure, a valve means at said air outlet for controlling airflow into said plenum, and means for discharging air into said secondplenum.
 2. The device of claim 1 wherein said modular test tray iscomprised of a plurality of individual modules having means to receiveelectrical components, means for selectively detachably securing saidindividual modules together, means for electrically connecting saidelectrical components received by said individual modules, and means forelectrically connecting said tray to test equipment.
 3. The device ofclaim 2 wherein said individual module comprises an electricallyinsulating body structure supporting at least two partially embeddedcomponents posts for receiving electrical components and at least twoembedded connector pins for receiving said means for electricallyconnecting said electrical components, with said components posts beingelectrically connected to said connector pins.
 4. The device of claim 3wherein said means for electrically connecting said components compriseselectrically conducting straps detachably secured to said connectorpins.
 5. The device of claim 4 wherein said electrically conductingstrap comprises intermittent strips of electrically conducting materialwith said strips being of sufficient length to electrically connect onlytwo of said connector pins of adjoining modules and said strips beingspaced apart so as to electrically connect consecutive pairs of saidconnector pins of adjoining modules.
 6. The device of claim 4 whereinsaid electrically conducting straps comprises a continuous strip ofelectrically conducting material.
 7. The device of claim 3 wherein saidbody structure has a front surface and a back surface, with said frontsurface having a plurality of protruding tongues and a first verticallydisposed channel and said back surface having a plurality of grooves anda second vertically disposed channel such that said tongues are matinglyreceived by said grooves of adjoining modules in tongue and groovefashion when a plurality of individual modules are linearly aligned withsaid first vertically disposed channel meeting said second verticallydisposed channel of adjoining modules to form vertically disposedchannels between adjoining modules.
 8. The device of claim 2 wherein themeans for selectively detachably securing said individual modulestogether comprises a bolt engaging said modules and threadably engagingnuts at each end thereof.
 9. The device of claim 1 wherein saiddiffusing means comprises a sheet containing a plurality of apertures.